TU-C-I-609-08: A Total-Imaging-System Generalized Performance Comparison of An X-Ray Image Intensifier and a Microangiographic System in Neurovascular Angiography: Effect of Focal Spot and Scatter

As useful as classical x-ray diffraction techniques have been, the ability to obtain x-ray diffraction images with extremely short exposure rimes opens up new opportunities for materials scientists, including real-time materials process control. This article briefly describes state-of-the-art systems for obtaining extremely rapid and real-time x-ray diffraction images and gives several examples of their applications for materials process control.Two generic electro-optical methods permit real-time viewing and recording of x-ray diffraction images. The first uses a low-intensity conventional x-ray tube source leading to a low-intensity diffraction image, which requires a high-gain electro-optical imaging system. The second uses either a high-intensity rotating anode, synchrotron, or flash x-ray source. Such a high-intensity source produces a high-intensity diffraction image, permitting use of a low-gain high-resolution electro-optical imaging system.Figure 1 schematically shows two types of image intensifier tubes which have been most often used to view x-ray diffraction images. By cascading three individual first generation image tube stages (Figure 1a), light gains as high as several million can be obtained. The second generation microchannel-plate image intensifier tube (Figure 1b) is similar to a single-stage first generation device except for the extremely important addition of a microchannel plate.

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Angular-dependent coherent scatter measured with a diagnostic x-ray image intensifier-based imaging system

Medical Physics ◽

10.1118/1.597720 ◽

1996 ◽

Vol 23 (5) ◽

pp. 723-733 ◽

Cited By ~ 49

Author(s):

M. S. Westmore ◽

A. Fenster ◽

I. A. Cunningham

Keyword(s):

Imaging System ◽

Image Intensifier ◽

Coherent Scatter ◽

X Ray

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XRMF applications of a monolithic, polycapillary, focusing x-ray optic

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100163666 ◽

1996 ◽

Vol 54 ◽

pp. 240-241

Author(s):

D. A. Carpenter ◽

Ning Gao ◽

G. J. Havrilla

Keyword(s):

Trace Elements ◽

Point Source ◽

Focal Spot ◽

Fluorescence Analysis ◽

X Rays ◽

Focal Distance ◽

Spot Diameter ◽

X Ray ◽

Focal Spot Diameter

A monolithic, polycapillary, x-ray optic was adapted to a laboratory-based x-ray microprobe to evaluate the potential of the optic for x-ray micro fluorescence analysis. The polycapillary was capable of collecting x-rays over a 6 degree angle from a point source and focusing them to a spot approximately 40 µm diameter. The high intensities expected from this capillary should be useful for determining and mapping minor to trace elements in materials. Fig. 1 shows a sketch of the capillary with important dimensions.The microprobe had previously been used with straight and with tapered monocapillaries. Alignment of the monocapillaries with the focal spot was accomplished by electromagnetically scanning the focal spot over the beveled anode. With the polycapillary it was also necessary to manually adjust the distance between the focal spot and the polycapillary.The focal distance and focal spot diameter of the polycapillary were determined from a series of edge scans.

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An Electron Diffraction Study on Litnerized Potato Starch

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010018166x ◽

1990 ◽

Vol 48 (1) ◽

pp. 580-581

Author(s):

Jean-Claude Jésior ◽

Roger Vuong ◽

Henri Chanzy

Keyword(s):

Electron Microscope ◽

Electron Diffraction ◽

Signal To Noise Ratio ◽

Potato Starch ◽

Image Intensifier ◽

Electron Diffraction Study ◽

Starch Granules ◽

X Ray ◽

Individual Grains ◽

Diamond Knife

Starch is arranged in a crystalline manner within its storage granules and should thus give sharp X-ray diagrams. Unfortunately most of the common starch granules have sizes between 1 and 100μm, making them too small for an X-ray study on individual grains. There is only one instance where an oriented X-ray diagram could be obtained on one sector of an individual giant starch granule. Despite their small size, starch granules are still too thick to be studied by electron diffraction with a transmission electron microscope. The only reported study on starch ultrastructure using electron diffraction on frozen hydrated material was made on small fragments. The present study has been realized on thin sectioned granules previously litnerized to improve the signal to noise ratio.Potato starch was hydrolyzed for 10 days in 2.2N HCl at 35°C, dialyzed against water until neutrality and embedded in Nanoplast. Sectioning was achieved with a commercially available low-angle “35°” diamond knife (Diatome) after a very carefull trimming and a pre-sectioning with a classical “45°” diamond knife. Sections obtained at a final sectioning angle of 42.2° (compared with the usual 55-60°) and at a nominal thickness of 900Å were collected on a Formvar-carbon coated grid. The exact location of the starch granules in their sections was recorded by optical microscopy on a Zeiss Universal polarizing microscope (Fig. 1a). After rehydration at a relative humidity of 95% for 24 hours they were mounted on a Philips cryoholder and quench frozen in liquid nitrogen before being inserted under frozen conditions in a Philips EM 400T electron microscope equipped with a Gatan anticontaminator and a Lhesa image intensifier.

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A Spectrum-Adaptive Decomposition Method for Effective Atomic Number Estimation Using Dual Energy CT

Electronic Imaging ◽

10.2352/issn.2470-1173.2020.14.coimg-293 ◽

2020 ◽

Vol 2020 (14) ◽

pp. 293-1-293-7

Author(s):

Ankit Manerikar ◽

Fangda Li ◽

Avinash C. Kak

Keyword(s):

Atomic Number ◽

Decomposition Method ◽

Traditional Approach ◽

Effective Atomic Number ◽

Dual Energy ◽

Performance Comparison ◽

Estimation Methods ◽

Dual Energy Ct ◽

Projection Data ◽

X Ray

Dual Energy Computed Tomography (DECT) is expected to become a significant tool for voxel-based detection of hazardous materials in airport baggage screening. The traditional approach to DECT imaging involves collecting the projection data using two different X-ray spectra and then decomposing the data thus collected into line integrals of two independent characterizations of the material properties. Typically, one of these characterizations involves the effective atomic number (Zeff) of the materials. However, with the X-ray spectral energies typically used for DECT imaging, the current best-practice approaches for dualenergy decomposition yield Zeff values whose accuracy range is limited to only a subset of the periodic-table elements, more specifically to (Z < 30). Although this estimation can be improved by using a system-independent ρe — Ze (SIRZ) space, the SIRZ transformation does not efficiently model the polychromatic nature of the X-ray spectra typically used in physical CT scanners. In this paper, we present a new decomposition method, AdaSIRZ, that corrects this shortcoming by adapting the SIRZ decomposition to the entire spectrum of an X-ray source. The method reformulates the X-ray attenuation equations as direct functions of (ρe, Ze) and solves for the coefficients using bounded nonlinear least-squares optimization. Performance comparison of AdaSIRZ with other Zeff estimation methods on different sets of real DECT images shows that AdaSIRZ provides a higher output accuracy for Zeff image reconstructions for a wider range of object materials.

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